1. Field of the Invention
The present invention generally relates to workflow processing and, more particularly to optimizing workflow execution by making intelligent decisions regarding service requests to perform workflow processes on one or more servers.
2. Description of the Related Art
Workflow processing technologies typically provide application integration capabilities, enabling a series of separate software components to be run in a defined sequence facilitating construction of larger solutions from individual software components. Workflow implementations are typically driven from a workflow definition, commonly captured as an eXtensible Markup Language (XML) document, that identifies the sequence of tasks to perform and data flows from one task to another. Thus, workflow engines provide the ability to string together functionality from different applications and servers into an overriding process.
This advancing technology allows application functionality to be customized into a flow that matches a company's business processes. Typically, by taking the output of one process and performing modifications to the structure of the output data, the input data for the next process is achieved. A series of iterations of this process provides the overall business process flow. In some cases, in order to take advantage of processing capabilities available on different servers, each of the processes of a workflow is performed as a service request issued by a workflow controller to a server which executes the process. As the servers are often available via the Internet or a company's Intranet, these service requests are often referred to as Web service requests. When a process has executed, the results are returned to the workflow flow controller which modifies the data as needed to the input data format needed for the next process.
A significant problem with workflow processing is the overhead of service requests. This problem may be illustrated by a simple exemplary workflow which contains three tasks: A, B, and C. Assuming there is some minor transformation of data that must happen between the tasks, which may be performed by functions AtoB and BtoC. It is further assumed that A, B, and C are services and that A and B in this workflow are performed on a first server, while C is performed on a second server. This exemplary workflow may thus be represented as the following:                doA—This service request goes to server1 for execution        AtoB—results from A are returned to controller and transformed        doB—This service request goes to server1 for execution        BtoC—results returned to controller, transformed        doC—This service request goes to server2 for executionAlthough both A and B are performed on server 1, results from A are transferred back to the workflow controller, formatted, and sent back to server 1. For some applications, the amount of data involved in each of these processes may be substantial (e.g., hundreds or thousands of database records), resulting in increased network traffic. Further, in some cases, the processes may be performed as part of a loop, requiring transfer of data for every iteration. If both A and B could be performed on server 1 without the service requests between them, however, the network bandwidth and overall execution time of the workflow may be reduced.        
While one solution to this problem may be to generate a single service to perform all tasks on a common server (e.g., a service to perform tasks A, B and C all at once), this solution is suboptimal and may lead to many large specialized services (e.g., one for each workflow). For example, many different workflows may require only B and C or only B. Making extremely large services to perform all tasks is less desirable than being able to combine or integrate different smaller services (e.g., one to perform A, one to perform B, and one to perform C) into a higher level service.
Accordingly, there is a need to optimize workflow processing, for example, by making intelligent decisions regarding service requests to perform workflow processes on one or more servers in an effort to reduce the total network and processing overhead associated with the service requests.